Properties of minerals

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Vocabulary

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Mineral: A naturally occurring solid that is inorganic that has a crystal structure and a definite composition.
Inorganic: Not made from living substances or from the remains of living substances.
Crystal: A solid that the atoms are arranged in an exact pattern that keeps repeating itself time after time.
Element: An object created of a single kind of atom.
Compound: A substance when two or more elements are joined together chemically.
Hardness: The level of the minerals calcium and magnesium in water.
Mohs Hardness Scale: A scale ranking ten minerals from softest to hardest to test the hardness in minerals.
Streak: The color of a mineral's powder when scratched.
Luster: The way a mineral reflects light from its surface.
Density: The deepness and mass of a given space.
Cleavage: A mineral's power to break with ease along surfaces that are flat.
Fracture: A way some minerals appear like when the mineral splits in a way that is not regular.
Fluorescence: The feature of some minerals in which it glares under ultraviolet light.

Outline

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What Is a Mineral?

• Geologists identified more than 3,000 kinds of minerals.
  • Of all of these minerals, only about 300 are common minerals.
  • About 20 minerals make up most of the rocks of Earth's crust.
• Naturally Occurring
  • To be classified as a mineral, a substance must occur naturally.
    • Cement, steel, brick, and glass all come from substances found in Earth's crust.
      • However, these objects are man-made.
        • These objects are not naturally occurring, so they are not classified as minerals.
• Inorganic
  • A mineral must be also inorganic.
    • A mineral can not be made from something that used to be a living thing.
• Solid
  • A mineral is always solid.
    • The particles of the minerals are packed tightly so that they cannot move.
      • A solid keeps its shape because particles can't move freely.
• Crystal Structure
  • The particles of a mineral line up in a pattern that repeats over and over.
• Cleavage and Fracture
  • The way a mineral splits apart can help to identify what mineral it is.
    • Cleavage is a property when the mineral splits along flat surfaces.
    • For example, the mineral Mica separates easily in only one direction, so this mineral has cleavage.
  • How a mineral looks when it breaks in an abnormal or irregular way is called fracture.
• Special Properties
  • Some rare minerals can be identified by special physical properties.
    • Minerals that glows under ultraviolet light is a property known as "fluorescence"
    • A mineral called Uraninite a few other minerals are radioactive.
    • A few minerals like Quartz have electrical properties.

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